Lubricating metal surfaces during cold working



in contact with the metal.

Patented Nov. 7, 1950 LUBRICATING METAL SURFACES DURING COLD WORKINGAlbert G. Rocchini, ,Springdale, and Richard J.

Neely, Oakmont, Pa., assignors to Gulf Research & Development Company,Pittsburgh Pa., a corporation of Delaware No Drawing. Application April7, 1948,

Serial No. 19,646

8 Claims.

1 This invention relates to lubricating metal surfaces during coldworking; and it comprises, in cold working a metal subsequently tobeannealed, a process improvement which resides in lubricating thesurfaces of said metal by means of a lubricant comprising a petroleumlubricating oil containing a small amount of an aniline derivativerepresented by the structural formula:

RIITH wherein R is a substituent selected from the class consisting of abenzyl group and hydrogen and R is selected from the class consisting ofmethoxy and ethoxy groups; all as more fully hereinafter set forth andas claimed.

The cold working of metals, such as the cold rolling, drawing, orstamping of aluminum, stainless steel, Monel metal, and the like, isordinarily followed by an annealing process. Annealing is oftenperformed in a gas-fired furnace wherein the products of combustion comeOwing perhaps to the restricted space adjacent the bulk of themetalsurfaces, and furthermore to the fact that conditions in thefurnace are not conducive to good combustion, it has been found thatconsiderable staining of the metal has reoxide, may appear in differentpositions on the strip and is believed to be caused by foreignmattersuch as dirt adhering; to the surface and being carried on thestrip into the annealing furnace. The third type of stain which mayappear in streaks or spots is believed to be a carbon formationresulting when the working lubricant is subjected to the reducingatmosphere in the annealing furnace. It is the formation of the lattertype of stain which the method of this invention inhibits orsubstantially retards.

In the past, the elimination of the stain resulting from the lubricanthas been accomplished by one of several alternatives. In one embodiment,the oil stain has been eliminated by. removingthe lubricating oil fromthe cold-Worked metal with a solvent prior to the annealing step. Otherembodiments have included chemically or mechanically removing the stainafterthe annealing operation. These embodiments, however, introduceexpensive processing steps.

The type of lubricant employed in cold working processes has also beenthe subject of many prior investigations. Among the lubricants whichhave been used are included animal oils, vegetable oils, minerals oils,and mixtures of these and water-oil emulsions. Animal and vegetable oilsare effective lubricants but they have certain disadvantages in thatthey are rather expensive, are not good coolants, and are easilyoxidized with the resultant development of rancidity. Furthermore,animal and vegetable oils, having high carbon residue values, have beenunsatisfactory in that unlessthey. are removed from the worked metalprior to its being annealed, they will leave stains in the form; ofcarbon deposits onthe metal when. it is subsequently annealed. 'Whilestraight mineral oils are satisfactory with respect to theircost,cooling properties, and stability,'they, as do the animal and vegetableoils, also have a disadvantage in that unless they are removed from theworked metal prior to its being annealed, they Will leave a stain on thesurface of the annealed metal. Water-oil emulsions are advantageous inthat they may easily be removed from metal surfaces by washing withwater prior toannealing, but this step in itself 'complicates'theworking process. Water-oil emulsions have a further disadvantage in thatwith repeated use as c.01d

'working lubricants, the Water tends to evaporate from the"water-oilemulsions thereby changing the ratio of water to oil. Since the ratio ofwater to' oil should be kept as uniform as possible to obtain optimumresults, frequent analysis of the lubricant is required thereby addingcomplexity to the process.

. It is the primary object achieved by this invention tov provide amethod of lubricating metal surfaces during cold Working. by means of alubricant which if allowed to remain on the metal during a subsequentannealing operation 3. cant comprising a petroleum lubricating oil whichwould normally tend to stain said metal surfaces during annealingthereof anda small amount, sufficient to inhibit or substantially retardthe formation of strain on the metal when it is subsequently annealed,ofan aniline derivativerepresented by the structural formula RNH dine,N-benzyl-para-anisidine, ortho-phenetidine, para-phenetidine,N-benzyl-ortho-phenetidine, N-benzyl-para-phenetidine, and the like.

'These compounds are advantageously added to a petroleum'lubricating oilof the roll oil and -draw oil type in an amount between about 1 (94%aluminum, 4.0% copper, 0.5% manganese and 0.5% magnesium). 1

In the practice of our invention any suitable lubricating oil base,whether it is derived from a parafiinic, naphthenic, or mixed basecrude, may be employed. Although it is seldom necessary in compositionsof the type disclosed herein, the lubricating oil base may contain oneor more of the so-called additive agents, including oiliness and extremepressure agents, viscosity index improvers, pour point depressants,

fietergents, foam inhibitors, and corrosion and oxidation inhibitors.The particular lubricant chosen depends on the type of cold-working op-=eration for which it is intended. For example,

oils used in cold rolling are generally highly refined and arerelatively volatile having viscosities between about 50 and 200 SUV at100-F., whereas oils used in drawing operations may have viscosities ashigh as 5000 SUV at 100 F. It is not intended to limit this inventionwith respect to the particular lubricating oil base.

The advantages to be obtained in accordance with our invention areillustrated in the following comparative laboratory tests made onahighly refined naphthenic base oil having a Saybolt Universal Viscosityof 53 at'100 F. and the same oil containing compounds of the typedisclosedherein. To simulate actual operating conditions of theannealing of cold-rolled aluminum, 1 ml. of the oil to be tested wasplaced between two aluminum plates (99.2% aluminum). The aluminum plateswere then placed in a, mufiie furnace for 30 minutes at a temperature of650 F., this being the tem'perature of the metal as determined by athermocouple. The plates were then removed andinspected. The appearance3 4 r the aluminum after annealing, as tabulated hereinbelow, wasdetermined by visual inspection and comparison with a blank set ofplates.

Compound Incorporated in a Highly Per Cent Appearance of RefinedNaphthem'c Base Oil (53 by Aluminum after SUV at 100 F.) WeightAnnealing Severe Stain. Slight Stain. Do. No Stain. Slight Stain.

Do. Do. No Stain.

Do. Do.

While the above compositions have been tested on cold-rolled aluminumplates, the method of our invention is advantageous when applied to anymetal being cold worked, and subsequently to be annealed. For instance,the method of our invention is applicable to the cold working ofnon-ferrous metals other than aluminum, such for example, as magnesiumor Monel metal, and is also satisfactory for the cold rolling ofstainless steel, particularly when such metals are to be annealed aftercold working, and where it is desirable that the surfaces of such metalsbe clean and bright after annealing. The method of our inventionobviatesthe expensive step of removing the oil film from the metal priorto its being annealed, and at the same time overcomes the staining whichnormally would occur in the annealing operation when employing astraight mineral lubricating oil as a lubricant for the cold working ofmetals.

While our invention has been described herein with particular referenceto certain specific embodiments thereof by way of illustration, it is tobe understood that the invention is not limited to such embodimentsexcept as hereinafter defined in the appended claims.

,an aniline derivative represented by the struc tural formula:

.RNH

wherein R is a substituent selected from the class consisting of abenz'yl group and hydrogen and R is selected from the class consistingof methoxy and ethoxy groups, and, without removing the film oflubricant from the surfaces of the cold-worked metal, annealing aid.coldworked metal.

2. A metal finishing process which comprises cold Working a metalwhile'maintaining on the surf-aces of said metal a film of lubricantconsisting essentially of a petroleum lubricating oil which wouldnormally tend to stain said metal surfaces during the annealing thereofand between about 1.0 and 10.0 per cent by weight of an anilinederivative represented by the structural formula:

ITIH:

wherein R is selected from the class consisting of methoxy and ethoXygroups, and, without removing the film of lubricant from the surfaces ofthe cold-worked metal, annealing said coldworked metal.

3. An aluminum finishing process which comprises cold rolling aluminumwhile maintaining on the surfaces of said aluminum a film of lubricantconsisting essentially of a highly refined relatively volatile petroleumlubricating oil which would normally tend to stain said aluminumsurfaces during the annealingthereof and between about 1.0 and 10.0 percent by weight of o-anisidine, and, without removing the film oflubricant from the surfaces of the cold-rolled aluminum, annealing saidcold-rolled aluminum.

4. An aluminum finishing process which comprises cold rolling aluminumwhile maintaining on the surfaces of said aluminum a film of lubricantconsisting essentially of a highly refined relatively volatile petroleumlubricating oil which would normally tend to stain said aluminumsurfaces during the annealing thereof and between about 1.0 and 10.0 percent by weight of p-phenetidine, and, without removing the film oflubricant from the surfaces of the cold-rolled aluminum, annealin saidcold-rolled aluminum.

5. A metal finishing process which comprises cold working a metal whilemaintaining on the surfaces of said metal a film'of lubricant consistingessentially of a petroleum lubricating oil which would normally tend tostain said metal surfaces during the annealing thereof and between about1.0 and 10.0 per cent by weight of an aniline derivative represented bythe structural formula:

of methoXy and ethoxy groups, and, without removing the film oflubricant from the surfaces of the cold-worked metal, annealing saidcoldworked metal.

6. An aluminum finishing process which comprises cold rolling aluminumwhile maintaining on the surfaces of said aluminum a film of lubricantconsisting essentially of a highly refined relatively volatile petroleumlubricating oil which would normally tend to stain said aluminumsurfaces during the annealing thereof and between about 1.0 and 10.0 percent by weight of N-benzyl-o-anisidine, and, without removing the filmof lubricant from the surfaces of the coldrolled aluminum, annealingsaid cold-rolled aluminum.

7. An aluminum finishing process which comprises cold rolling aluminumWhile maintaining on the surfaces of said aluminum a film of lubricantconsisting essentially of a highly refined relatively volatile petroleumlubricating oil which would normally tend to stain said aluminumsurfaces during the annealing thereof and between about 1.0 and 10.0 percent by weight of N -benzylo-phenetidine, and, without removing the filmof lubricant from the surfaces of the cold-rolled aluminum, annealingsaid cold-rolled aluminum.

8. An aluminum finishing process which comprises cold rolling aluminumwhile maintaining on the surfaces of said aluminum a film of lubricantconsisting essentially of a highly refined relatively volatile petroleumlubricating oil which would normally tend to stain said aluminumsurfaces during the annealing thereof and between about 1.0 and 10.0 percent by weight of N-benzylp-phenetidine, and, without removing the filmof lubricant from the surfaces of the colol-rol1ecl aluminum, annealingsaid cold-rolled aluminum.

ALBERT G. ROCCHINI. RICHARD J. NEELY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name 7 Date 2,257,869 Trautman Oct. 7, 19412,258,930 Haefner Oct. 14, 1941 2,308,690 Hughes Jan. 19, 1943 2,391,631Kingerley Dec. 25, 1945 2,403,238 Rosenstiehl July 2, 1946 2,430,400Hoelscher Nov. 4, 1947

1. A METAL FINISHING PROCESS WHICH COMPRISES COLD WORKING A METAL WHILEMAINTAINING ON THE SURFACES OF SAID METAL A FILM OF LUBRICANT CONSISTINGESSENTIALLY OF A PETROLEUM LUBRICATING OIL WHICH WOULD NORMALLY TEND TOSTAIN SAID METAL SURFACES DURING THE ANNEALING THEREOF AND BETWEEN ABOUT1.0 AND 10.0 PER CENT BY WEIGHT OF AN ANILINE DERIVATIVE REPRESENTED BYTHE STRUTURAL FORMULA: